The present invention relates to a diaphragm structure of digital still camera more particularly, to a diaphragm structure which has simple structure and low manufacture cost.
The conventional digital still camera (DSC) generally requires a mechanical-type light-blocking plate to block the light when exposure is finished and signal transform is executed in case that a non-progressive CCD (charge coupled device) is used. Therefore, the exposure time of CCD is controlled by the switch operation of the mechanical-type light-blocking plate.
FIG. 1 shows the conventional diaphragm structure for a DSC. As shown in this figure, the conventional diaphragm structure comprises an electromagnetic valve 10a, a connection means 11a and three light-blocking plates 12a. The electro-magnetic valve 10a is connected to those plates 12a through the connection means 11a such that the open/close of the plate 12a can be controlled by the electromagnetic valve 10a. 
However, the above-mentioned diaphragm structure of the DSC employs three light-blocking plates 12a. The structure is complicated, bulky and makes the manufacture cost high. Moreover, the kind of diaphragm structure is only suitable for placing in front of the lens or behind the lens and is not suitable for placing within the lens.
It is the object of the invention to provide a diaphragm structure for DSC, which comprises a lens, a first light-blocking plate, and a second light-blocking plate. The first and second light-blocking plates have a first and a second aperture, respectively, and are moveably arranged within the lens. The two light-blocking plates have linear movement within the lens such that the apertures on the two plates can be staggered to each other or aligned, thus closing or opening the diaphragm. The present invention employs two-plate type light-blocking plates, and thus has simple structure. The diaphragm of the DSC can be controlled by the linear motion of the two light-blocking plates to simplify the structure and its assembly and to reduce costs. Moreover, the linear motion of the light-blocking plates in the present invention enhances the reliability of the DSC and enables the diaphragm to install within the lens.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing in which: